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https://autopapyrus.com/guides/mercedes-benz/actros/replacing-the-comfort-module-body-control-module-bcm-on-a-mercedes-benz-actros/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Replacing the Comfort Module (Body Control Module, BCM) on a Mercedes-Benz Actros (MP4–MP5)

The BCM controls the cab's lighting, power windows, central locking, wipers, and other body functions. After replacement, the new module must be written with the configuration of this specific truck (parameterization), or its functions will not work. The exact removal procedure for this model is not documented in publicly available service materials, so the general principle is given below. Module location and mounting depend on the cab version.

Difficulty: Hard Time: 1-2 hours for the physical replacement, plus parameterization and function checks at a repair shop Steps: 10 Tools: Screwdriver and socket set (Torx and small sizes), plastic trim removal tools, multimeter, battery charger or power supply to maintain on-board voltage, antistatic gloves, Xentry/DAS diagnostic kit with a truck cable

Part

  • 🔩 Body control module (BCM) for Actros MP4/MP5, complete, matched exactly to your truck's equipment and VIN. Check the part number against the label on the old module. Without VIN coding, the module will not work. Price varies widely with equipment level. Used and remanufactured units are cheaper but carry a risk of incompatibility

Step by step

10 steps
  1. Pre-replacement diagnostics. Connect the diagnostic tool, then read and save the fault codes. Make sure the module is the real cause: check power and ground at the connectors, the fuses, the condition of the wiring harnesses, and any signs of moisture.
  2. Save the configuration. If the module still responds, back up its parameters or write down the equipment configuration. This will make setting up the new module easier.
  3. De-energize the truck. Turn the ignition off, remove the key, and disconnect the battery ground (main battery disconnect switch). Wait 5-10 minutes so the capacitors in the electronics discharge. Wear antistatic gloves.
  4. Gain access to the module. The module is located in the cab behind a trim panel or in a recess of the dashboard. Carefully remove the necessary panels with plastic trim tools. The clips are fragile, so do not force them.
  5. Disconnect the connectors. Photograph the connections and label the connectors. Each one has a lock or lever. Release it first, then pull the connector off. Check the contacts for oxidation and wear.
  6. Remove the module. Undo the fasteners and take out the module. Compare the part number on the old and new modules.
  7. Install the new module. Secure it, connect the connectors until they click, and refit the trim. Torque for the small fasteners is low and should follow the manufacturer's specification, so do not overtighten.
  8. Reconnect the battery ground and switch the ignition on. Before parameterization, the new module may show faults and not control its functions. This is normal at this stage.
  9. Parameterization and VIN matching. Using Xentry/DAS, perform the module installation procedure and write the configuration for your VIN and equipment. If required, synchronize it with the central gateway and the immobilizer control unit. This operation requires Mercedes-Benz Trucks diagnostic equipment, and without it the module will not work correctly.
  10. Check the functions. Check the lighting, marker lights, power windows, central locking, wipers, turn signals, instrument backlighting, and data exchange over the buses. Clear the faults and read the fault memory again.

Common mistakes and warnings

  • An incorrectly configured module can disable lights and signals, which is a road safety issue. Parameterization and VIN matching are done on dealer or specialist equipment, so if you lack experience and the proper tool, have a repair shop install and configure the module. Do not swap in a module from another truck "to try it." It is tied to the VIN, and trying to transfer it can lock up functions.